THE smoldering crisis in the Middle East has sparked perhaps the largest and most complex overseas deployment of United States military force since the Vietnam War. Basing US troops and jets in Saudi Arabia is a fateful step for both countries. For the US, it means achieving a long-sought goal of putting significant strength on the ground in the Gulf region. For the Saudis, it means visibly throwing in their lot with America - something they have long tried to avoid.
The US force, plus contingents from other UN nations, should provide a significant deterrent to further aggression in the region by Iraqi President Saddam Hussein. But by itself, the military presence is unlikely to bring a quick end to Iraq's occupation of Kuwait, US analysts say.
US troops could remain in the region for months as much of the world tries to squeeze Mr. Hussein via economic boycott. ``If I was him I'd hunker down now and try and cut the best deal I could,'' says James Wootten, a Congressional Research Service military specialist with extensive Middle East experience.
Throwing Iraq out of Kuwait militarily would involve daunting battles. Hussein has amassed considerable might there, and the multinational defense force moving into Saudi Arabia wouldn't be big enough for the task.
In any case, the 5,000 US troops will probably guard US airpower, not project power on the ground. Operating off Saudi airfields, US F-15 and F-16 jets, plus perhaps F-117A Stealth radar-avoiding fighters and B-52 bombers, will be the real muscle of the US presence.
Defense sources say that B-52s from Diego Garcia and two squadrons of F-15 fighters from the United States were being mobilized. The Saudis also have granted the US Air Force landing and refueling rights for F-111 fighter-bombers based in Turkey.
These warplanes could easily dominate the large but less well-equipped Iraqi air force. If Hussein does move into Saudi Arabia's vast expanse, his tanks could probably make much initial headway but would find their supply lines hard-pressed by the US.
Unlike Kuwait, Saudi Arabia ``isn't something Hussein could hold on to indefinitely,'' Mr. Wootten says.
The more likely US confrontation with Iraq will be over a naval blockade. US warships in the region could easily accomplish this task, greatly restricting the flow of oil exports and food imports on which Iraq depends.
Naval pickets would have to be set up in the Red Sea and northeastern Mediterranean. In the Gulf itself, blockading forces would probably just not allow oil tankers to sail north of Bahrain.
Analysts say that not only is a naval blockade easily accomplished, it's easily done multinationally - despite any threat posed by Iraqi air-to-ship missiles.
The aircraft carrier USS Saratoga and its 10-ship battle group, which includes the battleship USS Wisconsin, left home ports on the US East Coast Tuesday. Their arrival in about 10 days would bring to 49 the number of US warships in the region - including three carriers. In addition, two French frigates and a British destroyer are in the Gulf; two Soviet warships are on the way.
On the other hand, ``blockades don't solve things quick, and everyone always wants a quick solution,'' says Norm Friedman, naval author and Pentagon consultant.
Ever since President Carter declared that protecting the flow of Gulf oil was in the US national interest, Pentagon officials have been trying to obtain forward-basing rights in the region. Ironically, it has taken a threat to that oil flow to finally put US troops near the Gulf on the ground.
Even without a big base in the area, the US has quietly spent more than $1 billion in the past decade on setting up sites designed to support Gulf military action. In Oman, for instance, the Pentagon has built runways, refueling areas, storage sheds, and other facilities on Masirah Island and two mainland Omani air bases. According to declassified congressional budget documents, more than $100 million worth of US equipment is cached in Oman, including food, trucks, air-traffic control equipment, and air-to-air missiles.
The US Central Command has a small headquarters in Bahrain, and the US has access rights to facilities in Somalia and Kenya that could be used for Gulf support. The island of Diego Garcia in the Indian Ocean is the closest permanent US base, the only one between the Philippines and Italy. At Diego Garcia warehouse ships hold enough weapons for a Marine amphibious brigade and 7,000 tons of port-opening equipment for Army units.
In the past, Egypt and Saudi Arabia, among other nations, have resisted US overtures for base rights because of sensitivity in the Arab world to the appearance of foreign domination. That the Saudis have now agreed to the presence of US forces in uniform is a sign of their nervousness at Hussein's approach.
The key to the situation may not be the Saudis' willingness to host the US military, however, but their willingness to defy Iraq economically.